Signalling mechanisms underlying priming and tolerance of T cells

The primary mission of the immune system is to defend against invading pathogens. The normal healthy body can distinguish self from non-self antigens. When a new antigen is encountered, such discriminatory capacity would generate a productive immune response against invasive pathogens or exert antigen-specific tolerance, the latter to prevent harmful immune responses against self-components or non-dangerous food or environmental antigens. Peripheral tolerance plays an important role in preventing T cells response to self or harmless antigens. A breakdown in tolerance within an individual can result in the development of a variety of autoimmune disorders. Full T cell activation requires at least two signals. The first one is provided by the TcR recognizing cognate peptides derived from antigen in the context of appropriate MHC molecules expressed by antigen presenting cells (APC). The second is mediated by “co-stimulation” via interaction of CD28 on the T cell with CD80/86 on the APC. The clonal anergy is induced when the TcR is ligated in the absence of co-stimulation, one of the proposed mechanisms of peripheral tolerance, describes a state of long lasting unresponsiveness to antigen, in the T cell. Despite widely studies in this area, however, the mechanisms of induction of anergy and the efficient markers for diagnosis of anergy are still not clear. One of the mechanisms which contributes to forming tolerance is anergy, which can be defined as defect in cellular proliferation and IL-2 production. Furthermore, GTPase Rap1 has been reported to inhibit the generation of pERK signals and to accumulate in tolerant cells. However, most of previous studies have done by biochemical assessment of signaling in T cell lines or clones upon polyclonal stimulations in vitro, and thus has generated some conflicting data. For solving this problem, our lab has developed the technique, laser scanning cytometry (LSC), for observation of responses in individual antigen-specific T cells within their environmental niche within primary or secondary lymphoid tissue. By LSC, it has reported that there are significant differences in the amplitude and cellular localization of phosphorylated ERK signals when naïve and in vitro-primed and tolerized T cells respond to Ag. To further investigate the role of Rap1 by LSC, it revealed that counter regulation in Rap1 and phosphor-ERK expression during the maintenance phase of tolerance and priming of antigen-specific CD4+ T cells in vitro and in vivo. In T cells, the maintenance phase of anergy has been reported to reflect defective activation of transcription factor, such as c-Jun/c-Fos, that are involved in formation of the AP-1 complex, which is required for inducing transcription of the IL-2 gene and optimal activation and effector function of T cells. In turn, this appears to be determined by the lack of recruitment of the ERK, JNK and p38 MAPK signaling cascades. The small GTPase, Rap1, has long been implicated in such desensitisation of ERK, and the consequent reduced IL-2 production, observed in tolerised T cells. However, the most of these studies were processed with T cell lines or clones in vitro and as such are not necessarily representative of physiological responses of primary antigen-specific T cells. Consistent with the previous finding, we have extended these studies to investigate whether Rap1 plays a role in determining commitment to anergy and priming during induction and maintenance phases. As expected, analysis in the DNA synthesis during maintenance phase reported that the primed T cells exhibited a higher response than either naïve or anergic T cells, whilst the anergic T cells displayed an even lower DNA synthesis than naïve T cells undergoing a primary response. To further investigation in cytokine production of IL-2 and IFNγ at 24, 48 and 96 hour during the maintenance phase, consistent with previous studies, the primed T cells produced the highest levels of IL-2, relative to anergic cells with the lowest levels, at the first 24 hours after challenge with antigen. However, the IL-2 production from primed and anergic T cells both drop down from 48 hours and to very low level at 96 hours but accompanying with gradual increase of IFNγ production. This implicates both anergic and primed cells consumed IL-2 secreted in the early stage of maintenance phase for supporting following cellular differentiation. The assessment of cellular proliferation also indicates that both primed and anergic cells had undergone several rounds of division. Whereas the primed cells proliferated more and faster than anergic cells over the first two days, after that anergic cells were able to catch up with primed cells. Consistent with above proliferative responses, the primed T cells showed higher levels of ERK activation than anergic cells at day 1 but lower levels of ERK activation than anergic cells at day 3. Surprisingly, there is no difference in Rap1 activation between primed and anergic T cells during maintenance phase. The additional finding from cellular proliferation during maintenance phase revealed that both primed and anergic cells undergo clonal expansion during induction of priming and tolerance, which leads the further investigation in functional outcomes, MAPK signaling and mTOR pathways studies during induction phase. The primed cells exhibited higher levels of DNA synthesis than anergic cells at 48 hours whereas they had similar levels of DNA synthesis at 96 hours. The IL-2 and IFNγ production were only detectable within the first 48 hours but not 96 hour. Collaborating with the data from cellular proliferation indicates the IL-2 were consumed for promoting the cells survival and proliferation since both populations showed clear peaks representing differential numbers of cell division from day 2 (48 hour) onwards, whereas the primed cells proliferated more and faster than anergic cells during whole induction phase. Moreover, cyclic activation of ERK was seen in the primed T cells and at higher levels of activation than in the anergic population, which did not exhibit these kinetics in western blotting. Interestingly, the primed T cells exhibited slightly higher levels of Rap1 than anergic cells from 48 hour until 96 hour during induction phase. Consistent with data from in vitro, the proliferation response in mimicking physiological model also can be replicated. Additionally, the counter regulation in ERK and Rap1 activation also occurred during the induction of priming and tolerance, which is investigated by adenoviral gene transfer of Ad Rap1 S17N, an inactive mutant of Rap1. Furthermore, modulation of Rap1 expression with Ad Rap1 S17N in cells during induction of anergy, revealed that Rap1 activity acts to limit cellular proliferation and thus switching off Rap1 activity upregulates cellular proliferation to generate a phenotype more resembling priming of normal (or GFP-) T cells by antiCD3+anti-CD28, which showed higher proliferation that GFP- cells stimulated with anti-CD3 only. However, when these adenoviral transfer experiments were repeated in the more physiological model, the higher proliferation exhibited in anergic Ad Rap1 S17N transduced cells were not replicated, suggesting that the enhancing effect of Ad Rap1 S17N might be substituted by signals generated under these more physiological conditions. There did not appear any difference between anergic and primed cells in terms of ERK/Rap1 signalling during the induction phase and introduction of Ad Rap1 S17N did not modulate ERK activity in transduced cells treated with anti-CD3 or anti-CD3+anti-CD28, suggesting that Rap may target some other effector during the induction phase. To sum up these data, Rap signaling in anergy and priming as well as the use of the dominant negative construct suggested that Rap was not acting to suppress ERK activation during induction of anergy. The further investigation in the downstream targets, c-Myc, did not see any direct connection with ERK/Rap1 activation during induction of anergy and priming. Moreover, the primed T cells tend to skew to catabolic rather anabolic metabolic pathways, when compared to anergic T cells during the induction phase, as evidenced by the primed cells exhibiting upregulation and phosphorylation of AMPK and Raptor to inhibit mTORC1 funtion and in turn, lower levels of pp70 S6K. However, the expression of phosphorylated Rictor in anergic t cells was higher than that of primed T cells, indicating inhibition of mTORC2 in anergic T cells resulting in downregulation of AKT activation during this induction phase

An Integrated Edge and Fog System for Future Communication Networks

Put together, the edge and fog form a large diverse pool of computing and networking resources from different owners that can be leveraged towards low latency applications as well as for alleviating high traffic volume in future networks including 5G and beyond. This paper sets out a framework for the integration of edge and fog computing and networking leveraging on ongoing specifications by ETSI MEC ISG and the OpenFog Consortium. It also presents the technological gaps that need to be addressed before such an integrated solution can be developed. These noticeably include challenges relating to the volatility of resources, heterogeneity of underlying technologies, virtualization of devices, and security issues. The framework presented is a Launchpad for a complete solution under development by the 5G-CORAL consortium.This work has been partially funded by the H2020 collaborative Europe/Taiwan research project 5G-CORAL (grant num. 761586

Trends in epidemiology of hyperglycemia in pregnancy in Taiwan, 2008-2017

BackgroundHyperglycemia in pregnancy (HIP) increases the risk of adverse pregnancy outcomes. The increasing prevalence of overweight or obesity and the increasing proportion of pregnant women with advanced maternal age (AMA) in the recent decade may affect its prevalence. We analyzed the secular trend of HIP prevalence in 2008-2017 in Taiwan and investigated the impact of AMA in this study.MethodsThis cross-sectional study used data from Health and Welfare Data Science Center. Pregnant women who registered their data in the Birth Certificate Application in 2008-2017 were recruited. Diagnosis of HIP was defined by ICD-9-CM and ICD-10-CM codes.ResultsIn 2008-2017, 151,306-211,768 pregnant women were recruited in different years. The proportion of women with AMA increased from 15.8% to 32.1%. Meanwhile, the prevalence increased from 0.5% to 0.9% for preexisting diabetes, 0.2% to 0.4% for undiagnosed diabetes, and 11.4% to 14.5% for GDM. Maternal age was significantly associated with the prevalence of HIP. For women aged <30 years, 30-34 years and ≥35 years, the prevalence of preexisting diabetes were 0.51%, 0.75% and 1.24%, respectively (p<0.05); the prevalence of undiagnosed diabetes were 0.18%, 0.24% and 0.37%, respectively (p<0.05); and the prevalence of GDM were 10.57%, 14.77% and 18.13%, respectively (p<0.05). In all age groups, the prevalence of HIP increased over time in 2008-2017.ConclusionThe prevalence of HIP increased in Taiwan in 2008-2017, which may result from the increasing proportion of pregnant women with AMA and the change in the diagnostic criteria for GDM

A Riemann solver at a junction compatible with a homogenization limit

We consider a junction regulated by a traffic lights, with n incoming roads and only one outgoing road. On each road the Phase Transition traffic model, proposed in [6], describes the evolution of car traffic. Such model is an extension of the classic Lighthill-Whitham-Richards one, obtained by assuming that different drivers may have different maximal speed. By sending to infinity the number of cycles of the traffic lights, we obtain a justification of the Riemann solver introduced in [9] and in particular of the rule for determining the maximal speed in the outgoing road.Comment: 19 page

Tracking Cyber Adversaries with Adaptive Indicators of Compromise

A forensics investigation after a breach often uncovers network and host indicators of compromise (IOCs) that can be deployed to sensors to allow early detection of the adversary in the future. Over time, the adversary will change tactics, techniques, and procedures (TTPs), which will also change the data generated. If the IOCs are not kept up-to-date with the adversary's new TTPs, the adversary will no longer be detected once all of the IOCs become invalid. Tracking the Known (TTK) is the problem of keeping IOCs, in this case regular expressions (regexes), up-to-date with a dynamic adversary. Our framework solves the TTK problem in an automated, cyclic fashion to bracket a previously discovered adversary. This tracking is accomplished through a data-driven approach of self-adapting a given model based on its own detection capabilities. In our initial experiments, we found that the true positive rate (TPR) of the adaptive solution degrades much less significantly over time than the naive solution, suggesting that self-updating the model allows the continued detection of positives (i.e., adversaries). The cost for this performance is in the false positive rate (FPR), which increases over time for the adaptive solution, but remains constant for the naive solution. However, the difference in overall detection performance, as measured by the area under the curve (AUC), between the two methods is negligible. This result suggests that self-updating the model over time should be done in practice to continue to detect known, evolving adversaries.Comment: This was presented at the 4th Annual Conf. on Computational Science & Computational Intelligence (CSCI'17) held Dec 14-16, 2017 in Las Vegas, Nevada, US

Secondary Household Transmission of SARS, Singapore

Secondary household transmission of severe acute respiratory syndrome (SARS) was studied in 114 households involving 417 contacts. The attack rate was low (6.2%). Occupation of the index case was the factor that most influenced household transmission (adjusted hazard ratio for healthcare workers 0.157; 95% confidence interval 0.042 to 0.588)

Managing cardiac arrest with refractory ventricular fibrillation in the emergency department: Conventional cardiopulmonary resuscitation versus extracorporeal cardiopulmonary resuscitation

AbstractAimRefractory ventricular fibrillation, resistant to conventional cardiopulmonary resuscitation (CPR), is a life threatening rhythm encountered in the emergency department. Although previous reports suggest the use of extracorporeal CPR can improve the clinical outcomes in patients with prolonged cardiac arrest, the effectiveness of this novel strategy for refractory ventricular fibrillation is not known. We aimed to compare the clinical outcomes of patients with refractory ventricular fibrillation managed with conventional CPR or extracorporeal CPR in our institution.MethodThis is a retrospective chart review study from an emergency department in a tertiary referral medical center. We identified 209 patients presenting with cardiac arrest due to ventricular fibrillation between September 2011 and September 2013. Of these, 60 patients were enrolled with ventricular fibrillation refractory to resuscitation for more than 10min. The clinical outcome of patients with ventricular fibrillation received either conventional CPR, including defibrillation, chest compression, and resuscitative medication (C-CPR, n=40) or CPR plus extracorporeal CPR (E-CPR, n=20) were compared.ResultsThe overall survival rate was 35%, and 18.3% of patients were discharged with good neurological function. The mean duration of CPR was longer in the E-CPR group than in the C-CPR group (69.90±49.6min vs 34.3±17.7min, p=0.0001). Patients receiving E-CPR had significantly higher rates of sustained return of spontaneous circulation (95.0% vs 47.5%, p=0.0009), and good neurological function at discharge (40.0% vs 7.5%, p=0.0067). The survival rate in the E-CPR group was higher (50% vs 27.5%, p=0.1512) at discharge and (50% vs 20%, p=0. 0998) at 1 year after discharge.ConclusionsThe management of refractory ventricular fibrillation in the emergency department remains challenging, as evidenced by an overall survival rate of 35% in this study. Patients with refractory ventricular fibrillation receiving E-CPR had a trend toward higher survival rates and significantly improved neurological outcomes than those receiving C-CPR

Location of the Mandibular Canal and Thickness of the Occlusal Cortical Bone at Dental Implant Sites in the Lower Second Premolar and First Molar

The objective of this study was to evaluate the location of the mandibular canal and the thickness of the occlusal cortical bone at dental implant sites in the lower second premolar and lower first molar by using dental cone-beam computed tomography (CBCT). Seventy-nine sites (47 second premolar and 32 first molar sites) were identified in the dental CBCT examinations of 47 patients. In this study, 4 parameters were measured: (1) MC—the distance from the mandibular canal to the upper border of the mandible; (2) CD—the distance from the mandibular canal to the buccal border of the mandible; (3) MD—the distance from the mandibular canal to the lingual border of the mandible; (4) TC—the thickness of the cortical bone at the occlusal side. A statistical analysis was employed to compare the size and differences between these 4 parameters at the lower second premolar and lower first molar. Regarding the MC and MD, the experimental results showed no statistical difference between the first molar and second premolar. However, the TC for the second premolar was greater than that of the first molar. Thus, careful consideration is necessary in choosing the size of and operation type for dental implants

Bevacizumab Dose Affects the Severity of Adverse Events in Gynecologic Malignancies

In this retrospective study, we investigated adverse events and outcomes in patients treated with bevacizumab for ovarian, fallopian tube, or primary peritoneal cancers at a single hospital. We determined the cumulative incidences of various bevacizumab-related adverse events and the correlation between dose and adverse event incidences. We analyzed data from 154 patients that received 251 rounds of bevacizumab as first-line, first salvage, >2 salvage treatments. Adverse events of any grade were observed in 121 (78.6%) patients; at least one grade 3 or 4 adverse event occurred in 32 (20.8%) patients. The two most common events were proteinuria (38.3%) and hypertension (33.8%). The first-line treatment group displayed significantly higher frequencies of hypertension (52.7% vs. 18.9% vs. 15.5%, p < 0.001), wound complications (9.1% vs. 0% vs. 1.2%, p = 0.010), arthralgia (29.1% vs. 11.3% vs. 8.3%, p = 0.003), and reduced range of joint motion (14.5% vs. 5.7% vs. 3.6%, p = 0.046), compared to those in the first and >2 lines salvage groups, respectively (Kruskal–Wallis test). The cumulative incidences of all grades and grades 3/4 of hypertension cumulative incidence plateaued at around 30% for all grades and 10% for grades 3 and 4, at bevacizumab doses above 8080 and 3510 mg, respectively. The proteinuria cumulative incidence plateaued at around 35% for all grades and 3% for grades 3 and 4, at bevacizumab doses above 11,190 and 4530 mg, respectively. We concluded that, in this realistic clinical population, different kinds and higher cumulative incidences of adverse events were observed compared to those reported in previous clinical trials. Moreover, bevacizumab doses showed cumulative toxicity and plateau effects on hypertension and proteinuria